Earth and Sky

Earth is the third planet from the Sun, characterized by its layers: a core, mantle, and crust. Its surface is mostly water (oceans), with land masses and a protective atmosphere that supports life. Sky refers to the visible outer layer of Earth's atmosphere, where clouds form, weather occurs, and the Sun, Moon, stars, and planets are visible. The atmosphere shields us from harmful space radiation and helps regulate temperature. The sky's changing appearance—from day to night—results from Earth's rotation, giving us the sunrises, sunsets, and celestial observations we see regularly.